Rather than heavily protecting backdoors with hardcore packers, many malware authors evade heuristic detections by obfuscating only key portions of an executable. Often, these portions are strings and resources used to configure domains, files, and other artifacts of an infection. These key features will not show up as plaintext in output of the strings.exe utility that we commonly use during basic static analysis.

The FireEye Labs Obfuscated String Solver (FLOSS) uses advanced static analysis techniques to automatically deobfuscate strings from malware binaries. You can use it just like strings.exe to enhance basic static analysis of unknown binaries.